Optical detection systems are often utilized to qualitatively, quantitatively, or semi-quantitatively determine the presence or concentration of an analyte within a test sample. Unfortunately, conventional optical detection systems generally suffer from at least one of two major problems. One problem is that the optical detection system, although sensitive and accurate, is too expensive and complex for use by ordinary consumers, such as non-technical personnel at doctor's offices, clinics, home, rest homes, etc. To reduce cost and complexity, other optical detection systems have thus been developed. However, such systems typically achieve a reduction in cost and complexity through a concurrent loss in sensitivity. Although such a loss in sensitivity is not necessarily critical in all applications, it becomes increasingly problematic when the system is used in conjunction with membrane-based assay devices. Specifically, analyte concentration is diluted in such devices by fluid flowing through the membrane. Due to such a low analyte concentration, the level of background interference (i.e., “noise”) may simply be too great relative to the detection signal to achieve an accurate result.
As such, a need currently exists for a more “balanced” optical detection system for assay devices that is easy to use, inexpensive, and possesses an increased signal-to-noise ratio.